God requires repentance for the Spirit to resume it's communion with us. He requires it for our sake, not His. Repentance not only gets our heart back in line with Him, but with others as well. It clears our conscience as we're not trying to hide anything from God anymore. It frees us and allows us to be in the moment with others.
So where does Christ fit into this? Right in the middle. Repentance opens the pathway for the Mediator, Christ, to bridge the gap in our relationships. Christ holds everything together (Col 1:17). Everything must pass through Him, including relationships. In his book, The Cost of Discipleship, Dietrich Bonhoeffer further explains the concept of Christ as Mediator in our relationships.
"There is no way from one person to another. However loving and sympathetic we try to be, however sound our psychology, however frank and open our behavior, we cannot penetrate the incognito of the other man, for there are no direct relationships, not even between soul and soul. Christ stands between us, and we can only get into touch with our neighbors through Him."